Enhancement of flavor with 2,5,5-trimethyl-hepta-2,6-dienal and lower alkyl acetals thereof

ABSTRACT

A new aldehyde, 2,5,5-trimethyl-hepta-2,6-dienal and acetals thereof having a woody taste and flavor, and useful for enhancement of coffee flavored foodstuffs. The enhancement is achieved by the addition of a small but effective amount of said aldehyde or acetals thereof.

United States Patent [191 Dietrich et al.

[ 51 Nov. 25, 1975 [73] Assignee: General Foods Corporation, WhitePlains, N.Y.

22 Filed: Oct.l2, 1972 21 Appl. No.: 297,103

[52] US. Cl 426/534; 260/601 R; 260/615 A; 426/594 [51] Int. Cl A2311/26 [58] Field of Search 426/65 [56] References Cited UNITED STATESPATENTS 3,702,253 11/1972 Winter et a1 426/65 3,767,429 10/1973 Burke426/65 Primary Examiner.loseph M. Golian Attorney, Agent, orFirmDaniel 1. Donovan [57] ABSTRACT A new aldehyde,2,5,S-trimethyl-hepta-Z,6-dienal and acetals thereof having a woodytaste and flavor, and useful for enhancement of coffee flavoredfoodstuffs. The enhancement is achieved by the addition of a small buteffective amount of said aldehyde or acetals thereof.

10 Claims, No Drawings ENHANCEMENT OF FLAVOR WITH2,5,S-TRIMETHYL-HEPTA-2,6-DIENAL AND LOWER ALKYL ACETALS THEREOFBACKGROUND OF THE INVENTION The present invention relates to2,5,5-trimethyl-hepta-2,6-dienal and certain acetals thereof, founduseful in the area of flavor alteration whether by enhancement of flavorcharacteristics in a substance, modification of flavor or by complete orpartial masking of flavor. Still more particularly, the inventionrelates to incorporation of woody flavor compounds selected from thegroup consisting of 2,5,5trimethyl-hepta-2,6-dienal, its acetals andmixtures thereof in coffee to reduce the caramel, acid, and sour flavorof coffee; modify and improve the green, earthy, and buttery notes ofcoffee; and add a desirable woody, regular coffee flavor to thefoodstuff. The compounds employed have particular application to solubleand regular coffee which may be deficient in a woody flavor.

DESCRIPTION OF THE PRIOR ART In the field of flavor enhancement, it hasbeen general practice to employ synthetic and naturally isolatedcompounds and compositions to enhance or mask the flavor of foodstuffs.Generally, isolation of single flavors does not allow one to predictequivalent flavors since compounds. of greatly differing structure havebeen found to produce approximately the same flavor character whilecompounds of similar structure fre quently differ appreciably in taste.-Consequently, the identification of desirable flavor componentsrequires synthesis and trial of individual candidates until compoundsare identified which have desirable flavors.

For many years, coffee technologists have searched for flavor enhancingcompounds which would produce the flavor note generally described bycoffee experts as woody." Recently, a number of woody flavored 2-nonenals and 2-nonenols have been identified to have this character. Inthe course ofinvestigating those compounds, we have discovered thecompounds employed in the composition and process of this invention.

SUMMARY OF THE INVENTION The general purpose of this invention is toprovide compounds and compositions containing compounds which willenhance coffee flavored foodstuffs by inparting to them a regular coffeeflavor characterized by experts as woody.

The flavor enhancement is achieved by the addition of a small buteffective amount of woody flavored compounds selected from the group of2,5,5-trimethyl-hepta-2,6-dienal and the acetals derived therefrom tothe foodstuff to be flavored. The compounds, singly or mixtures, producea coffee flavor when added in minute amount, generally in parts perbillion, to water or foodstuffs. 1

It is an object ofthis invention to provide compounds for the flavoralteration of foodstuffs, particularly coffee deficient in woody flavor.

It is a further object of this invention to, describe processes foremploying woody compounds in concentrates useful for enhancing theflavor of foodstuffs, particularly coffee.

DESCRIPTION OF THE INVENTION The compounds employed in this inventionare 2.5.5- trimethyl-hepta-2,6-dienal and acetals prepared there fromwhich when added to foods, particularly coffee, produce a flavorcharacterized by coffee experts as woody. These woody flavored compoundsare charac terized by the following formulas:

Wherein R is preferably lower alkyl, particularly methyl.

The 2,5,S-trimethyl-hepta-Z,6-dienal is prepared by oxidizing2,5,S-trimethyl-hepta-Z,6-diene with selenium dioxide. The2,5,5-trimethyl-hepta-2.o-diene is prepared by reactingl-chloro-3-methyl-2-butene with magnesium in ether following the methodof Henne. et al..I.A.C.S. 63, 3474 (1941 The l-chloro-3-methyl-2- buteneis prepared according to the procedure ofJones and Chorley, J.C.S. 832(l946). Alternatively. 2,5,5- trimethyl-hepta-2,6-diene is prepared bythe Wurtz reaction using magnisum and phenyl chloride (isoprene andhydrochloric acid) in ether J.Am. Chem. Soc., 76, 5403 I954).

The compounds of Formula II are prepared by reacting the selectedcompound of Formula I with a trialkylorthoformate, and alkanol and anacid catalyst such as ammonium chloride.

Representative of the woody compound of this invention are 2,5,5-trimethyl-hepta-2,6-diene dimethyl acetal,2,5,5-trimethyl-hepta-2,6-dienal, 2,5,5-trimethylhepta-2,6-diene diethylacetal and the like. I

The compounds for Formulas I and II are useful for enhancing the flavorof food. They enhance coffee flavored foodstuffs where a regular coffeeflavor generally characterized by coffee experts as woody is desired butdeficientsuch as regular coffees like Robustas, decaffeinated coffee,soluble coffee; and coffee flavored foods such as icings, drinks, Postumbrand beverage. desserts, candies, and the like.

The Compounds of Formulas l and II and mixtures thereof give coffeeflavor when added to water or foodstuffs. In addition to imparting tocoffee a regular. coffee-like flavor having a strong woody note. thesecompounds exert a balancing effect on other desirable coffee notes suchas the green, earthy, and buttery flavors while masking the undesirableacid, sour, and caramel flavors. The compounds also exert a blendingeffect on the overall brew flavor of soluble coffee. The compounds ofFormulas I and Il may be added to any coffee including soluble coffee,decaffeinated coffee either regular or soluble and regular roasted andground coffee. The compounds of Formulas I and Il may also beincorporated with other coffee flavor fractions, both synthetic andthose obtained from coffee, and with these flavors exert a balancingeffect while strengthening the woody regular coffee flavor.

Depending on the flavor desired, the comounds of Formulas I and II canbe incorporated in the foodstuff either alone. combined with otherflavor ingredients, or with carriers. In flavoring soluble coffee, thewoody compounds may be either added to regular coffee prior toextraction. to coffee percolate prior to drying, or may be plated on ormixed with the dried coffee. Since only a minute amount of the flavorand aroma compounds are needed, it is preferred to incorporate them inan edible carrier or concentrate prior to addition to the coffee. Theconcentrate or carrier may be liquid, syrup, or solid, depending on itsultimate use. For example, the compounds of Formulas I and 11 may beincorporated in ethanol, propylene glycol; oils such as cottonseed,coffee, peanut. or the like; or other edible vehicles to form aconcentrate for convenient shipping. storage, and addition to thefoodstuff. For example. oil containing a compound of Formulas I and IIor mixtures thereof may be plated on soluble coffee to enhance itsflavor or alternatively, an oil containing the flavor compound may beincorporated in extract and dried. Dry concentrates containing thecompounds of Formulas I and II or mixtures thereof may also be preparedby employing film-forming compositions such as gums like gum arabic,pectins, alginates, and the like; starch breakdown products such asCapsul (National Starch), Morex 1918 (Corn Products), Maltrin (GrainProcessing), and the like; candy melt systems and other art-recognizedstabilizing or diluent systems. In forming any concentrate, theproportions of the compounds of Formulas I and 11 therein is notcritical provided the level of flavoring is controlled to give anenhanced coffee flavor and an even distribution of the flavorconcentrate throughout the foodstuff to be flavored.

Minute amounts of the compounds of Formulas I and II are sufflcient toproduce an enhancement of coffee flavor in foodstuffs. For example, inregular or soluble coffee beverages, say from about 1 to 1.5% coffeesolids, the compounds can be employed to produce a change in cup flavorand aroma but a change which cannot be described as a particular flavor.Alternatively, proportions sufficient to be recognized as woody may beemployed. The threshold flavor level for the compounds of this inventionis about ppb with a woody flavor evident at about 80 ppb. At 2 ppm theflavor of the compounds change and become aromatic and not desirable forcoffee flavoring.

The flavor impact of the compounds of Formulas I and II and mixturesthereof is easily adjusted by varying the concentration of the flavoringcompounds employed in the foodstuff. It is to be expected thatadjustment will be necessary depending on the particular foodstuffsbeing flavored. Initial panel screening by those of ordinary skill inthe art is used to determine the threshold and proper strength level forthe particular foodstuff in which the flavor is employed.

The compounds of Formulas I and II are particularly useful for balancingthe natural flavor of spray-dried and freeze dried soluble coffee,decaffeinated coffee, both soluble and regular, and regular coffee ofvarious blends or single varieties, particularly those having highRobusta content. The flavor compounds are particularly preferred forimparting a woody flavor to the preceding coffees deficient, partiallyor totally, in that flavor. However, even at levels below the woodythreshold level, balancing of flavor is noted by expert tasters. Theflavor compounds of Formulas I and II are also particularly useful when'combined with steamgenerated natural coffee aromas or enhancers wherethere is produced a blending or smoothing of coffee aroma and flavor anda masking of the undesirable sourness and caramel characteristics oftenassociated with coffee. Similar improvement is noted for mixtures ofsynthetic and natural coffee aromas and flavors. In addition to theapplication of the compounds of Formulas I and II in foodstuffs, theseflavoring agents may also be employed in edible substances such aspharmaceuticals, where a woody regular coffee note is desired.

The invention is now illustrated but not limited by the followingexamples:

EXAMPLE I A solution of 2,5,5-trimethyl-hepta-2.6-diene (68 g. 0.5 mole)in ethanol ml) is heated to 50C. A solution of selenium dioxide (28 g,0.25 mole) in warm ethanol (45 ml) is added over a 15-minute period in anitrogen atmosphere. The resulting mixture is heated to reflux or 45minutes. The solution is cooled and the selenium removed by filtration.The filtrate is concentrated and distilled to give a mixture of2,5,5-trimethylhepta-2,6-dienal and its corresponding alcohol (2,5,5-trimethyl-hepta-Z,6-dienol, b.p. 94C/l0 mm). The mixture is redistilledusing a spinning band column to give 2,5,5-trimethyl-hepta-2,6-dienal,b.p. 70C/l3 To obtain a maximum yield of the aldehyde, the mixture ofaldehyde and alcohol is treated with activated manganese dioxide toconvert the alcohol to the aldehyde.

EXAMPLE II 2,5,5-trimethyl-hepta-2,6-dienal (10.9 g, 0.5 mole),trimethyl orthoformate (10.6 g, 0.1 mole), methyl alcohol (10 ml), andammonium chloride (0.5 g) are heated at reflux for 3 hours undernitrogen. The mixture is cooled. filtered, diluted with water andextracted with ether. The ether layer is washed with 5% sodiumbicarbonate followed by water and dried over sodium sulfate. The ethersolution is concentrated and distilled under vacuum to give2,5,5-trimethyl-hepta-2,6-diene dimethyl acetal.

When the methyl alcohol is replaced by ehtanol and the trimethylorthoformate replaced by triethyl orthoformate,2,5,5-trimethyl-hepta-2,6-diene diethyl acetal is obtained.

EXAMPLE III A mixture of 0.02 mol. (3.1 g) of2,5,5-trimethylhepta-2,6-dienal, 0.02 mol. of triethyl orthoformate and0.46 ml of ethyl alcohol were stirred at room temperature in a bath ofcold water. On the addition of 2 drops of boron trifluoride etherate thetemperature rose to about 45, falling almost at once to room temperature, at which the mixture was stirred for 17 hours. About 1.5 g ofanhydrous potassium carbonate was added, the mixture was stirred for 10minutes more, filtered and concentrated. Rapid distillation gave afraction consisting mainly of the desired acetal, which was purified byfurther distillation to yield 2,5,5-trimethylhepta-2,6-dienal diethylacetal b.p. 9596C/10 mm.

When trimethyl orthoformate and methyl alcohol are substituted for theirethyl homologs there is obtained 2,5,5-trimethyl-hepta-2,6-dienaldimethyl acetal b.p. 7 1C/ 10 mm.

EXAMPLE IV Roasted coffee extract is prepared from roasted coffee bynormal commercial techniques to obtain a percolate of -50% coffeesoluble solids. Sufficient 2,5,5- trimethyl-hepta-2.6-dienal is added togive a woody, natural coffee flavor at 1.35% coffee solids in aqueoussolution. The mixture is placed in cooled trays and frozen at athickness of less than one-half inch. A frozen mixture of extract andaroma is then freeze dried in a commercial drying unit to produce afreeze dried coffee having enhanced woody flavor.

Instead of freeze drying the enhanced percolate, it may be spray driedinstead. If desired, a portion of the percolate may be employed to fixthe flavor compound by any known drying procedure and then mixed withunenhanced dried soluble coffee.

What is claimed is:

' 1. A process for enhancing the flavor of foodstuffs comprising addingthereto a compound selected from the group consisting of2,5,5-trimethyl-hepta-2,6-dienal, lower alkyl acetals of2,5,5-trimethyl-hepta-2,6- dienal and mixtures thereof in an amounteffective to impart a woody flavor to the foodstuff.

2. The process of claim 1 in which the foodstuff is coffee.

3. The process of claim 2 in which the coffee is decaffeinated.

4. The process of claim 2 in which the coffee is roasted coffee.

5. The process of claim 2 in which the coffee is soluble coffee.

6. The process of claim 2 in which the compound is2,5,5-trimethyl-hepta-2.6-dienal.

7. The process of claim 6 in which the coffee is soluble coffee.

8. The process of claim 7 in which the soluble coffee is deficient in awoody flavor.

9. A foodstuff having as an active flavoring ingredient an amount ofcompound selected from the group consisting of2,5,S-trimethyl-hepta-Z.6-dienal, lower alkyl acetals of2,5,5-trimethyl-hepta-2,6-dienal and mixtures thereof effective toimpart a woody flavor to the foodstuff.

10. The foodstuff of claim 9 wherein the foodstuff is coffee deficientin woody flavor.

1. A PROCESS FOR ENHANCING THE FLAVOR OF FOODSTUFFS COMPRISING ADDINGTHERETO A COMPOUND SELECTED FROM THE GROUP CONSISTING OF2,5,5-TRIMETHYL-HEPTA-2,6-DIENAL AND MIXTURES THEREOF OF2,5,5-TRIMETHYL-HEPTA-2,6-DIENAL AND MIXTURES THEREOF IN AN AMOUNTEFFECTIVE TO IMPART A WOODY FLAVOR TO THE FOODSTUFF.
 2. The process ofclaim 1 in which the foodstuff is coffee.
 3. The process of claim 2 inwhich the coffee is decaffeinated.
 4. The process of claim 2 in whichthe coffee is roasted coffee.
 5. The process of claim 2 in which thecoffee is soluble coffee.
 6. The process of claim 2 in which thecompound is 2,5,5-trimethyl-hepta-2,6-dienal.
 7. The process of claim 6in which the coffee is soluble coffee.
 8. The process of claim 7 inwhich the soluble coffee is deficient in a woody flavor.
 9. A foodstuffhaving as an active flavoring ingredient an amount of compound selectedfrom the group consisting of 2,5,5-trimethyl-hepta-2,6-dienal, loweralkyl acetals of 2,5,5-trimethyl-hepta-2,6-dienal and mixtures thereofeffective to impart a woody flavor to the foodstuff.
 10. The foodstuffof claim 9 wherein the foodstuff is coffee deficient in woody flavor.